Semiconductor devices include one or more semiconductor chips having connections that are protectively enclosed in a package, for example by encapsulation material and/or mold compound. Semiconductor packages are commonly employed in a wide range of electronic devices, such as mobile devices, and in a wide variety of applications, including telecommunication and automotive applications. The semiconductor packages are typically connected to a circuit board of the electronic device, for example by solder balls or other connectors.
During use, the semiconductor package generates heat that has the potential to induce stress between the chip and the package and between the package and the circuit board. The coefficient of thermal expansion (CTE) for the semiconductor chip is generally different than the CTE for the package substrate and the encapsulation/mold material of the semiconductor package. The CTE of the semiconductor package is generally different than the CTE of the circuit board to which the package is installed. During use, the thermal changes have the potential to stress the connections between the chip and the package and between the package and the circuit board. The difference in the CTE for these components can potentially result in loss of electrical connection or in poor electrical connection due to stress-induced fatigue cracks at the connections. In addition, mechanical shock that arises when a mobile electronic device is dropped has the potential to detach the solder connections between the semiconductor package and the circuit board.
It is desirable to provide semiconductor packages that are resistant to CTE-induced thermal stresses and mechanical shock. For these and other reasons there is a need for the present invention.